Green Building Services GBS - Simple, Smart, Sustaining Solutions

Buildings are responsible for 48 percent of all greenhouse gas emissions¹. But a new renovation in Portland, Ore. bucked this statistic, providing a crucial example of how buildings can greatly reduce their carbon emissions using standard technology. The innovative project exceeds the American Institute of Architects (AIA) Architecture 2030 Challenge and is poised to achieve a LEED (Leadership in Energy and Environmental Design) Platinum certification.

The 2030 Challenge gives new buildings tiered performance targets for reductions in carbon emissions, and existing buildings have a single target – a 50 percent reduction. When the board of AIA Portland selected an historic 1888 stable in the vibrant Pearl District as the Portland AIA Center for Architecture’s (CFA) new home, meeting the 50 percent reduction was a major goal.

At project start-up, GBS orchestrated an eco-charrette on sustainable building techniques open to anyone from the AIA membership. The project team included HOLST Architecture, Glumac, KPFF Consulting Engineers, Mayer/Reed and Luma Lighting Design. GBS played a key role in helping the design team integrate green building strategies that emphasized energy efficiency. The resulting achievement was an 83 percent reduction in carbon emissions.

The building is all-electric, and the team combined off-the-shelf split system technology and natural ventilation components in creative ways to reach the goal. This integrated system allowed the project to optimize performance while controlling costs.

GBS used energy design simulation to identify the most cost-effective energy-saving strategies, quantify the synergies between the strategies, and ultimately determine the relative energy savings and carbon emission reductions from the final design as compared to an ASHRAE baseline.

Natural ventilation is critical to the building’s overall energy reduction. The team designed a vertical stack ventilation strategy with a damper that opens for night flushing. Warm air exhausts through four roof turbines, and very low-energy turbine fans draw cool night air through the space until the temperature reaches a set point. In addition, the roof turbines serve as a built-in passive redundant system for the booster fan, further reducing the load of the HVAC units.

Four basic split-system heat pumps maintain comfort when natural ventilation is insufficient. Using smaller separate systems reduced the distribution requirements as well as overall energy consumption. This hybrid HVAC/natural ventilation system is uniquely suited to the temperate Pacific Northwest climate.

Additional energy-conserving features include increased insulation and a garden wall that provides building shade. Large street-facing operable windows with low-e glazing are connected to the control system to switch off or set back the HVAC system when the windows are open. Dual-technology occupancy and sweep sensors and daylight dimming systems keep energy for lighting to a minimum.

The board also plans to install a photovoltaic array, creating an even larger gain in energy conservation. With the array, the project will realize an 85 percent emission reduction, and the subsequent purchase of carbon offsets will make the CFA 100 percent carbon neutral.

Water conservation was another priority of the board, and the project included a 6,000-gallon cistern to capture rainwater for reuse in toilets and for landscape irrigation. The combination of water conserving fixtures and rainwater reuse cut annual water use by 87 percent.

The board’s leadership, commitment and creativity spawned a remarkable project that others can learn from. Using readily available technology, the AIA CFA shows that sustainable, climate-conscious design is within reach for everyone.

Alan Scott, Principal, Green Building Services, Inc.

1) Data from the U.S. Energy Information Administration